Mobile terminal devices such as smart phones tend to include many sensors. The sensors are used for users' operations of the mobile terminal devices or used to detect behaviors of the users.
Among the mobile terminal devices, there is a mobile terminal device that is configured so that until an interrupt is provided from outside the mobile terminal device, a CPU that processes applications is in a sleep state in order to reduce power to be consumed.
In addition, there is a mobile terminal device that includes a CPU and a microcomputer that consumes lower power than the CPU, controls a sensor and processes data acquired from the sensor. In the mobile terminal device having this configuration, the microcomputer may control the sensor and process the data acquired from the sensor during the time when the CPU is in a sleep state.
In order for a mobile terminal device to calculate, on the basis of the result of a measurement executed by an acceleration sensor, the number of steps that a user has taken, the mobile terminal device acquires several tens of acceleration data items per second. It is, however, sufficient if the process of calculating the number of the steps from the acquired acceleration data items is executed before the user views the number of the steps. Thus, the data acquired from the acceleration sensor may not be processed in real time in some cases.
For such cases, there is a mobile terminal device provided with a microcomputer that has a storage unit that temporarily store data acquired from a sensor. In this mobile terminal device, when a CPU releases a sleep state (or wakes up), the microcomputer transmits data accumulated in the storage unit to the CPU and may thereby reduce the frequency of changes from the sleep state to a wake state and vice versa and save power to be consumed. The mobile terminal device increases a period of time for the CPU to be in the wake state or the sleep state and thereby saves power to be consumed.
As the period of time for the CPU to be in the wake state is increased, the difference between the time when the data is acquired from the sensor and the time when the CPU processes the data acquired from the sensor increases. For an application for which data, such as data entered from a keyboard for a game, is transferred from the sensor to the CPU in real time, it is desirable that the frequency of the transfer of the data be increased in some cases.
In order to appropriately set the frequency of transfer of data from the sensor to the CPU for the application and save power to be consumed, it is preferable that an appropriate frequency of transfer of data be set in the mobile terminal device.
In mobile terminal devices that are used in recent years, however, not only applications that are pre-stored in the mobile terminal devices but also applications that are separately downloaded by users are used in many cases. The downloaded applications are not managed by manufacturers of the mobile terminal devices. Thus, information of the frequencies of transfer of data for the downloaded applications is not pre-stored in the mobile terminal devices.
Japanese Laid-open Patent Publication No. 2004-145875 is an example of related art.